[1.7.2] Last Stand STN

Hi! I need some ideas for how to make a last stand against the oncoming horde! This map will have no fort, but plenty of blocks to build one with! How would you like for me to create the landscape for something like this? Also, some specials will be available. What would you like to see? This is an open idea, so anything goes! Mostly no bad ideas, but TNT for players is out of the question!